A/C Performance

[JohnMirada]

We have 2015 Mirada 35LS with two 13.5 A/C units. When the outside temp gets in the high 80's and above, it seems the front A/C can't keep up and inside temp will be between 81 & 84 with the A/C unit running continuously. We live in Florida and will encounter those higher outside temps a lot. The 15.0 A/C unit is an option on this model. Will upgrading to that improve our A/C performance? Dealer has already looked at our unit twice and said everything is working as it should.

[Wheels Down]

My 15K unit on my Flagstaff TT was also having a problem keeping up with the workload of cooling the TT.
I took the filters off for cleaning and noticed the factory installers got pretty liberal with the expanding foam insulation around the return ducts. I took a knife and cut out some sizable chunks of the dried foam. One side had the wiring harness, so use caution if you try this.
The unit seemed to work noticeably better. Might be worth a look.
RMc

[Bluepill]

Factory installs are notorious for being done poorly. Loose/disconnected ducts, air leakage to unconditioned space, etc.

Do as good an inspection as you can for obvious faults.

This link may help:

http://www.forestriverforums.com/for...5-a-13490.html

And this:

http://www.forestriverforums.com/for...ure-83163.html

Search function will give you more info

[Casey r]

Along with what bluepill says about enlarging the ducts i found the divider between the air intake and delivery to the ducts had 1/2 gap all around. I used duct tape to close that gap and provided a lot better air flow out to the ducts.

[manderson2228]

We live in GA with a 35kb and i wouldn't consider running two 13.5k units. We upgraded to the 15k and it does keep ours cool on hot days. If it were me i'd upgrade to the 15k units and try again. Down here in the south it's just too hot. My dealer doesn't even order them 13.5k units at all they only get 15k units. I'd guess Florida is even worse!

[JohnMirada]

Another twist in the story. For the last two nights the rear A/C will come on (actually I think only the blower) for almost a minute an then turn off for about 10 seconds and then come on again. After several cycles of this it sounds like the compressor comes on and the the unit probably runs for about 10 minutes and everything is ok until the next cycle. Driving me batty.

[JohnMirada]

Thanks Manderson 2228 - I can't believe our dealer orders Florida units with small A/C's.

[manderson2228]

Originally Posted by JohnMirada

Thanks Manderson 2228 - I can't believe our dealer orders Florida units with small A/C's.

I joke all the time that I bought 2 camping air conditioners and they threw the RV in for free

[Pcracer]

Originally Posted by JohnMirada

Another twist in the story. For the last two nights the rear A/C will come on (actually I think only the blower) for almost a minute an then turn off for about 10 seconds and then come on again. After several cycles of this it sounds like the compressor comes on and the the unit probably runs for about 10 minutes and everything is ok until the next cycle. Driving me batty.

I just emailed Dometic about the exact same thing. They said if ONLY the fan is kicking on and off it is a design of the thermostat and is ok. If the compress is kicking on and off take it to a service center. I agree. It is annoying.

[Bluepill]

Originally Posted by Pcracer

I just emailed Dometic about the exact same thing. They said if ONLY the fan is kicking on and off it is a design of the thermostat and is ok. If the compress is kicking on and off take it to a service center. I agree. It is annoying.

Link on that deal here:

http://www.forestriverforums.com/for...es-118846.html

[Pcracer]

Interesting. Guess I'll put fan on "hi" at night so it won't keep waking me up.

[JohnMirada]

Pcracer - interesting. It's really annoying when you're trying to sleep. If it's a function of the thermostat I wonder if changing the thermostat with a different brand would help. Thanks for your input. By the way this problem has nothing to do with fan speed - it comes on and off on high - I have fan speed set to auto.

[cmalberto]

Originally Posted by JohnMirada

We have 2015 Mirada 35LS with two 13.5 A/C units. When the outside temp gets in the high 80's and above, it seems the front A/C can't keep up and inside temp will be between 81 & 84 with the A/C unit running continuously. We live in Florida and will encounter those higher outside temps a lot. The 15.0 A/C unit is an option on this model. Will upgrading to that improve our A/C performance? Dealer has already looked at our unit twice and said everything is working as it should.

Have you addressed the heat problem in the front? The front glass is brutal with the heat that it lets in. We have used reflectix before and it is quite economical. I also bought a screen to put up inside...Both options help a great deal.

The key is getting the heat off the glass. I have measured temps over 110. We ultimately bought a Magne-shade which goes on the outside. This was our best solution. We can now run and keep the AC around 78 with no problems during the heat of the day. The back unit is run cooler to help compensate for the extra work the front has to do.

Bottom line - it has been quite comfortable this year so far...and we leave the front shade up so we can see outside.

[JohnMirada]

Actually I use the Prompt RV windshield sunscreen. It is an external sunscreen so it blocks the sun's rays before they hit the glass. I also have an oscillating tower fan between the front seats to try and get the air moving around. Before our next outing in 2 weeks I'm going to try the reflectix (sp) in the side windows as there is quite a gap between the MCD side shades and glass allowing the heat to build up. The front of the coach is noticeably warmer than the rest of the coach. If time allows I'm also going to remove the access panels in the front overhead cabinets and stuff insulation in there.

[cmalberto]

Originally Posted by JohnMirada

Actually I use the Prompt RV windshield sunscreen. It is an external sunscreen so it blocks the sun's rays before they hit the glass. I also have an oscillating tower fan between the front seats to try and get the air moving around. Before our next outing in 2 weeks I'm going to try the reflectix (sp) in the side windows as there is quite a gap between the MCD side shades and glass allowing the heat to build up. The front of the coach is noticeably warmer than the rest of the coach. If time allows I'm also going to remove the access panels in the front overhead cabinets and stuff insulation in there.

That's the idea - stop the heat/sun from warming the glass and the air between the glass and the shades. Also if you have cabinets up top, these are good places to store your extra pillows - they act as insulation here too!